Gas turbo-blower apparatus for generating and delivering combustion gases and reduction gases to a blast furnace

ABSTRACT

A gas turbine is utilized as the prime mover to drive a compressor in a device for supplying air at the proper temperature and pressure for combustion of carbon within a blast furnace and for supplying reducing gases at the proper temperature and pressure to assist in the reduction of iron oxides within a blast furnace.

[4 Dec. 11, 1973 GAS TURBO-BLOWER APPARATUS FOR GENERATING AND DELIVERING [56] References Cited UNITED STATES PATENTS COMBUSTION GASES AND REDUCTION GASES TO A BLAST FURNACE 3,304,074 2/1967 Atherton.................. 266/30 [75] Inventor: John H. Stevens, Peters Township,

Washington County, Pa.

Primary ExaminerGerald A. Dost Attorney-Donald S. Ferito [73] Assignee: United States Steel Corporation, Pittsburgh, Pa.

[57] ABSTRACT A gas turbine is utilized as the prime mover to drive a I22] Filed: Sept. 11

Appl. No.: 287,934 compressor in a device for supplying air at the proper temperature and pressure for combustion of carbon within a blast furnace and for supplying reducing gases at the proper temperature and pressure to assist in the reduction of iron oxides within a blast furnace.

[52] U S Cl 266/29, 266/25 [5]] Int. F27b 11/10 [58] Field of Search 75/41, 42; 266/13,

266/25, 28, 29, 30 1 Claim, 1 Drawing Figure REDULT/O ZONE GAS TURBO-BLOWER APPARATUS FOR GENERATING AND DELIVERING COMBUSTION GASES AND REDUCTION GASES TO A BLAST FURNACE The present invention relates generally to blast furnaces and more particularly to improved apparatus for supplying combustion blast gas and reducing gas to a blast furnace.

One of the problems inherent in the blast furnace process of producing iron is caused by the dual function of the blast furnace, i.e., reduction and melting. The gases leaving the melting zone of the blast furnace must have a temperature higher than the melting point temperature of iron, which is approximately 2800F. At the same time the maximum temperature in the reduction zone should be lower than the melting point temperature of iron oxide which is approximately 2580F.

It is, accordingly, the primary object of my invention to provide improved apparatus for supplying combustion blast gas at proper temperature and pressure to a blast furnace and simultaneously supply reducing gas at the proper temperature and pressure to the blast furnace to achieve an optimum operating atmosphere in the reduction zone of the furnace.

It is a more specific object of my invention to provide apparatus as generally set forth in the above-stated object wherein a gas driven turbine is utilized to drive a gear set which, in turn, independently drives a pair of compressors, one of which supplies combustion blast gas to the combustion zone of the furnace and the other supplies reducing gas to the reduction zone of the furnace at proper pressures. The apparatus also includes afterburners to improve the quality of the reducing gas and a heat exchanger to bring both gases to proper temperature before being introduced into the blast furnace.

The most pertinent art references of which I am aware are U. S. Pat. Nos. 3,216,711 and 3,216,712, both dated Nov. 9, 1965.

The above and other objects will become more apparent after referring to the following specification and attached drawing, in which:

The single FIGURE of the drawing is an elevational view of a blast furnace, partly in section, provided with the apparatus of the invention.

The present invention contemplates providing heated and pressurized gas to the combustion zone of a blast furnace by means of tuyeres attached to one of two v bustle pipes encircling the furnace. The high sensible heat of the incoming gas plus the reaction of 0 with carbon in the furnace will generate the required temperature. The apparatus of the invention also provides heated and pressurized gases in the form of C0 H 0, and N: to an area above the combustion zone of the furnace by means of tuyeres attached to the other bustle pipe encircling the furnace. The C0; and H 0 upon entering the furnace will react with carbon in the furnace to form CO and H These reactions are endothermic and as such will absorb a large amount of sensible heat from the combustion gases. C0 and [-1 formed by this reaction are the necessary reducing gases required in the blast furnace process of reducing iron oxides to iron. The apparatus of the invention succeeds in setting the proper temperatures in the proper places of the blast furnace and generates additional reducing gases while doing so, thereby greatly increasing the operating efficiency of the blast furnace process.

Referring more particularly to the drawing, reference character 2 designates generally a blast furnace having the apparatus of the invention incorporated therewith. The apparatus of the invention includes a first bustle pipe 4 encircling the lower portion of the blast furnace and a second bustle pipe 6 encircling the furnace spaced above the first bustle pipe. Bustle pipe 4 is adapted to receive heated and pressurized combustion blast gas and deliver it to the combustion zone of the furnace through tuyeres 8 which are connected with the bustle pipe 4 and lead into the combustion zone of the furnace. Bustle pipe 6 is adapted to receive heated and pressurized reducing gas and deliver it to the furnace by means of tuyeres 10 which are connected with bustle pipe 6 and lead to the interior of the furnace just below its reduction zone.

The gas turbo-blower apparatus of the invention, des ignated generally by reference numeral 12, includes a gas turbine engine, designated generally by reference numeral 14. The gas turbine engine 14 is comprised of an air inlet 16, a fuel-burning combustion chamber 18 connected by one end with the air inlet 16 for receiving air therefrom, and a turbine 20 connected with the opposite end of the combustion chamber for receiving exhaust gases from the combustion chamber and being driven thereby.

A gear box 22 is directly connected with and driven by the turbine by means of a shaft 24. A first compressor 26 is connected with and driven by a power shaft 28 projecting from the gear box 22. The compressor 26 is disposed in a first duct 30 which has an air inlet 32 at one end for supplying air to compressor 26 and is connected at its other with an inlet on the bustle pipe 4.

An exhaust gas duct 34 is connected with the housing 36 of the turbine 20 for receiving and venting, by means of a vent. 38 at its end, exhaust gases from the turbine 20.

A third duct 40 is connected by one end and communicates with exhaust duct 34 short of its vented (38) end and extends therefrom to a connection with an inlet on bustle pipe 6. A diverting valve 42 is provided at the junction of duct 34 and duct 40 for diverting some of the turbine exhaust gas from'duct 34 into the duct 40 and to a compressor disposed in duct 40. Compressor 44 is connected with and driven by apower shaft projecting from the gear box 22.

Afterburners 48 are provided in the duct 40 upstream of the compressor 44 which burn sufficient fuel, natural gas or fuel oil, to eliminate all excess 0, in the compressed exhaust gas flowing from compressor 44. At this point, upstream of the afterburners 48 in the duct 40, the exhaust gas components are C0,, H 0 and N and the temperature of the gas is approximately A heat exchanger 50 is disposed in and common to ducts 30 and 40 adjacent their connections with the inlets of bustle pipes 4 and 6, respectively. The heat exchanger 50 transfers heat from the superheated exhaust and reducing gases traveling through the duct 40 to the compressed combustion air traveling to the furnace via the duct 30. Passage of the combustion air and reducing gas through the heat exchanger raises the sensible heat of the combustion blast gas to optimum operating temperature and lowers the sensible heat of the reducing gas to a temperature compatible for maintaining an optimum reducing atmosphere in the reduction zone of the furnace.

While I have shown but one embodiment of my invention, other adaptations and modifications may be made without departing from the scope of the following claim.

I claim:

1. In a blast furnace having a combustion zone and a reduction zone above said combustion zone the improvement therewith of apparatus for generating and delivering heated and pressurized combustion blast gas and reducing gas to said blast furnace, said apparatus comprising a first bustle pipe encircling said furnace and having an inlet for receiving combustion blast gas under pressure, tuyeres leading from said first bustle pipe to the interior of said combustion zone, a second bustle pipe encircling said furnace and having an inlet for receiving reducing gas under pressure, tuyeres leading from said second bustle pipe to the interior of said furnace immediately below the reduction zone thereof, a gas turbine engine including an air inlet, a fuelburning combustion chamber connected by one end with said air inlet for receiving air therefrom, and a turbine connected with the opposite end of said combustion chamber for receiving exhaust gases from said combustion chamber, said turbine being driven by said exhaust gases, a gear box directly connected with and driven by said turbine, a first compressor and a second compressor connected with and driven by separate power shafts projecting from said gear box, said first compressor being disposed in a first duct having an air inlet at one end and connected with said inlet in said first bustle pipe at its other end, a second duct connected with said turbine for receiving exhaust gases therefrom, said second duct having a vent opening in the end thereof remote from said turbine, a third duct connected at one end with said second duct intermediate said turbine and said vent and at its other end to the inlet of said second bustle pipe, a diverter valve adjacent the junction of said second duct and said third duct for selectively diverting exhaust gas from said second duct to said third duct, said second compressor being disposed in said third duct adjacent said diverter valve, afterburners in said third duct for receiving compressed exhaust gases from said second compressor, a heat exchanger disposed in and common to said first and third ducts adjacent the ends thereof connected with the inlets in said first and second bustle pipes. 

1. In a blast furnace having a combustion zone and a reduction zone above said combustion zone the improvement therewith of apparatus for generating and delivering heated and pressurized combustion blast gas and reducing gas to said Blast furnace, said apparatus comprising a first bustle pipe encircling said furnace and having an inlet for receiving combustion blast gas under pressure, tuyeres leading from said first bustle pipe to the interior of said combustion zone, a second bustle pipe encircling said furnace and having an inlet for receiving reducing gas under pressure, tuyeres leading from said second bustle pipe to the interior of said furnace immediately below the reduction zone thereof, a gas turbine engine including an air inlet, a fuelburning combustion chamber connected by one end with said air inlet for receiving air therefrom, and a turbine connected with the opposite end of said combustion chamber for receiving exhaust gases from said combustion chamber, said turbine being driven by said exhaust gases, a gear box directly connected with and driven by said turbine, a first compressor and a second compressor connected with and driven by separate power shafts projecting from said gear box, said first compressor being disposed in a first duct having an air inlet at one end and connected with said inlet in said first bustle pipe at its other end, a second duct connected with said turbine for receiving exhaust gases therefrom, said second duct having a vent opening in the end thereof remote from said turbine, a third duct connected at one end with said second duct intermediate said turbine and said vent and at its other end to the inlet of said second bustle pipe, a diverter valve adjacent the junction of said second duct and said third duct for selectively diverting exhaust gas from said second duct to said third duct, said second compressor being disposed in said third duct adjacent said diverter valve, afterburners in said third duct for receiving compressed exhaust gases from said second compressor, a heat exchanger disposed in and common to said first and third ducts adjacent the ends thereof connected with the inlets in said first and second bustle pipes. 